Disposable absorbent articles, such as diapers, pull-on diapers, training pants, adult incontinence pads, wipes, facial tissue, toilet tissue, napkins, paper towels and the like are often manufactured and/or packaged on a high-speed production line where individual articles may move along a production path at a speed of hundreds of meters per minute, and manufacturers of articles are continually trying to increase manufacturing speed. However, in order to increase the speed of a manufacturing process, larger, more powerful drive motors are typically required to increase the operational speed of the various components in the process. Such motors can be costly and take up an undesirable amount of floor space in the manufacturing facility. Further, increasing the roll speed may undesirably affect the timing of the upstream and/or downstream processes, for example, by increasing the precision needed to synchronize the upstream and/or downstream processes with the new, faster roll speed.
In conventional manufacturing processes, it is not uncommon for rolls, sometimes referred to as drums or cylinders, to be used to transport articles from one component or portion of the process to another. Known folding rolls and/or transport rolls typically have a substantially uniform, two-dimensional, curved surface, and an article disposed on the surface of such a roll is generally disposed in a “flat-out” configuration on the roll surface (i.e., no slack in the article which could cause bunching, wrinkles, looseness, or the like). Thus, the number of flat-out articles of a particular length that can be accommodated by a roll may be directly determined by the circumference of the roll. For example, a conventional folding drum having a circumference of 600 mm can accommodate no more than three articles having a length of 200 mm each, assuming the articles do not overlap one another. If the length of each article is increased, for example to 300 mm, and the circumference of the roll is unchanged, then only two articles can be accommodated by the roll per revolution, assuming articles do not overlap. Conversely, reducing the size of the articles, for example to 100 mm each, without changing the circumference or speed of the roll may permit the roll to accommodate up to 6 articles per revolution. While it may be possible to increase the size of the roll, replacing a roll can be expensive and the larger size may undesirably affect the relative positions and/or timing of other components in the manufacturing process. Increasing the speed of the roll may increase the rate at which articles are processed, but, as pointed out above, it typically requires providing a larger motor, which may not be desirable. In addition, if variable speed servo motors are used, increasing the power of the motor may increase the inertia of the motor and potentially offset any speed increases desired. Decreasing the size of an article may increase the rate at which the articles can be processed. But decreasing the size of an article may not be a practical option for certain articles such as disposable diapers, training pants, or other articles that are typically manufactured in particular sizes to fit different sizes of wearers.
Accordingly, it would be desirable to provide a process and apparatus for increasing the number of articles transported on a folding drum without increasing the size or speed of the drum.